Not an answer to your problem, but will put you back to the top.
What OS are you using?
On a setup that I have used device drivers came on the driver disk that came with the firewire card.
When you have selected 'movie capture'select 'edit' under preferences. It will tell you the 'DV device is unavailable, say OK and you should go to a preferences window. Go to 'Device control' and 'options'. A sub window 'device control options' will show. Make sure the 'device brand is at 'generic'. and 'device model' is at 'generic' Select 'ok', 'ok' and this will bring you back to the capture subwndow.
Your brand of samsung may or may not show. (Use it if it does). Try that.
Also of note is that my setup requires my camera to be connected to the firewire and switched on before booting the computer.
If you have already tried these steps --- just ignore. But hang around there are other more clued up video users here.
ps forgot to mention used the firewire drivers under W2k. Did not use those on CD and premiere found the device under generic.
Hope this may be of some help.
Regards Brian j